René's URL Explorer Experiment

{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"【0097_Week07】学习总结","articleBody":"/**\r\n     * 选择排序\r\n     *\r\n     * @param arr\r\n     */\r\n    public void selectSort(int[] arr) {\r\n        if (arr.length == 0) return;\r\n        int maxIndex;\r\n        for (int i = 0; i \u003c arr.length; i++) {\r\n            maxIndex = i;\r\n            for (int j = i + 1; j \u003c arr.length - i; i++) {\r\n                if (arr[j] \u003e arr[maxIndex]) {\r\n                    maxIndex = j;\r\n                }\r\n            }\r\n            int tmp = arr[arr.length - i];\r\n            arr[arr.length - i] = arr[maxIndex];\r\n            arr[maxIndex] = tmp;\r\n        }\r\n    }\r\n\r\n    /**\r\n     * 插入排序\r\n     *\r\n     * @param arr\r\n     */\r\n    public void insertSort(int[] arr) {\r\n        if (arr.length \u003c= 1) return;\r\n        for (int i = 1; i \u003c arr.length; i++) {\r\n            int preIndex = i - 1, current = arr[i];\r\n            while (preIndex \u003e= 0 \u0026\u0026 arr[preIndex] \u003e current) {\r\n                arr[preIndex + 1] = arr[preIndex];\r\n                preIndex--;\r\n            }\r\n            arr[preIndex + 1] = current;\r\n        }\r\n    }\r\n\r\n    /**\r\n     * 冒泡排序\r\n     *\r\n     * @param arr\r\n     */\r\n    public void bubbleSort(int[] arr) {\r\n        if (arr.length == 0) return;\r\n        for (int i = 0; i \u003c arr.length; i++) {\r\n            for (int j = i + 1; j \u003c arr.length; j++) {\r\n                if (arr[i] \u003e arr[j]) {\r\n                    int t = arr[i];\r\n                    arr[i] = arr[j];\r\n                    arr[j] = t;\r\n                }\r\n            }\r\n        }\r\n    }\r\n\r\n    /**\r\n     * 快速排序\r\n     *\r\n     * @param arr\r\n     * @param begin\r\n     * @param end\r\n     */\r\n    public void quickSort(int[] arr, int begin, int end) {\r\n        if (begin \u003e= end) return;\r\n        int pivot = partition(arr, begin, end);\r\n        quickSort(arr, begin, pivot - 1);\r\n        quickSort(arr, pivot + 1, end);\r\n\r\n    }\r\n\r\n    public int partition(int[] arr, int begin, int end) {\r\n        int pivot = end, count = begin;\r\n        for (int i = begin; i \u003c end; i++) {\r\n            if (arr[i] \u003c arr[pivot]) {\r\n                int tmp = arr[i];\r\n                arr[i] = arr[count];\r\n                arr[count] = tmp;\r\n                count++;\r\n            }\r\n        }\r\n        int tmp = arr[pivot];\r\n        arr[pivot] = arr[count];\r\n        arr[count] = tmp;\r\n        return count;\r\n    }\r\n\r\n    /**\r\n     * 归并排序\r\n     *\r\n     * @param arr\r\n     * @param left\r\n     * @param right\r\n     */\r\n    public void mergeSort(int[] arr, int left, int right) {\r\n        if (arr.length \u003c= 1) return;\r\n        if (right \u003c= left) return;\r\n        int mid = (left + right) \u003e\u003e 1;\r\n        mergeSort(arr, left, mid);\r\n        mergeSort(arr, mid + 1, right);\r\n        merge(arr, left, mid, right);\r\n    }\r\n\r\n    /**\r\n     * 归并排序的合并\r\n     *\r\n     * @param arr\r\n     * @param left\r\n     * @param mid\r\n     * @param right\r\n     */\r\n    public void merge(int[] arr, int left, int mid, int right) {\r\n        int[] temp = new int[right - left + 1];\r\n        int i = left, j = mid + 1, k = 0;\r\n        while (i \u003c= mid \u0026\u0026 j \u003c= right) {\r\n            temp[k++] = arr[i] \u003e= arr[j] ? arr[i++] : arr[j++];\r\n        }\r\n        while (i \u003c= mid) temp[k++] = arr[i++];\r\n        while (j \u003c= right) temp[k++] = arr[k++];\r\n        for (int t = 0; t \u003c temp.length; t++) {\r\n            arr[left + t] = temp[t];\r\n        }\r\n    }","author":{"url":"https://github.com/JiangJiang77","@type":"Person","name":"JiangJiang77"},"datePublished":"2020-03-01T09:25:29.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":0},"url":"https://github.com/1270/algorithm005-class02/issues/1270"}